. Diseases of wheat, oats, barley, and rye. Grain. 16 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 48 differences in severity of rust lie chiefly in the amounts of rust infection on the leaves. Loss in yield is severe when rust infec- tion occurs early and continues throughout the growing season. Leaf rust causes a reduction in number of kernels per head and. Fig. 3.—Leaf rust on wheat. The dark spots scattered over the leaves, between the veins, are the rust pustules. These are orange-red during the growing season and produce the rust spores by which the disease is spread. in kernel volume even w
. Diseases of wheat, oats, barley, and rye. Grain. 16 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 48 differences in severity of rust lie chiefly in the amounts of rust infection on the leaves. Loss in yield is severe when rust infec- tion occurs early and continues throughout the growing season. Leaf rust causes a reduction in number of kernels per head and. Fig. 3.—Leaf rust on wheat. The dark spots scattered over the leaves, between the veins, are the rust pustules. These are orange-red during the growing season and produce the rust spores by which the disease is spread. in kernel volume even when shriveling of kernels is not evident. The per cent of leaf area occupied by leaf rust in Illinois over a 34-year period is shown in fig. 2. Specialized varieties or physiologic races of leaf rust, like those of stem rust, page 18, show considerable selectivity with regard to the wheat varieties they attack; over 140 such races have been found to occur in the world. In 1957, 19 physiologic races were detected in the United States; race 15 was most abundant. Appearance.—As the name implies, leaf rust of wheat is found mainly on the leaves, but it may occur on the stems, espe- cially that part of a stem between the head and the flag leaf, and occasionally on the chaff. The disease first appears on the older leaves and spreads up the plant to the flag leaf as the season ad- vances. The rust shows as small, round or oblong, raised, orange-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Boewe, Gideon Herman, 1895-. [Urbana]
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Keywords: ., bookcentury1900, bookcolle, bookpublisherurbana, booksubjectgrain
